Aquaculture Engineering

Practical - 3
Experiment No 1 - Determination of area of a plot

Aim:
To plot the boundaries of a field and to determine its area. Equipments: Chain, Tape, Ranging rods, Arrows, Cross staff etc.

Procedure:

• Fix the ranging rods at each end of the straight line portion of the boundary and also where the boundary takes a curve, and then fix rods at constant interval.
• A chain line is run through the center of the plot from one end to the other, so that the offsets to the boundaries on either side of it are fairly equal.
• The chain is stretched along the chain line starting from one end.
• The cross- staff is moved along the chain line and offsets are takenat the points where the ranging rods occur.
• The chainages and offsets are noted in the field book. Chainages are entered in the central column and offsets are entered opposite to chainage on the right or left of the chainage depending on where they occur.
• To check the accuracy of the fieldwork, the chainages of the points of intersection of the chain line and the boundaries should be noted and the lengths of the boundary lines determined by the direct measurement. After the field work is over, the survey is plotted to a suitable scale.